摘要:

THE ANALYST. MAY, 1899. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS. THE monthly meeting of the Society was held on Wednesday evening, April 12, in the Chemical Society’s Rooms, Burlington House, the President, Mr. W. W. Fisher, M. A., occupying the chair. The minutes of the previous meeting were read and confirmed. Certificates of proposal for election to membership in favour of the following candidates were read for the second time : Julian L. Baker, F.I.C. ; Herbert Edward Burgess ; Louis Charles Deverell ; Julius Lewkowitsch ; F. R. O’Shaughnessy ; Arthur Marshall; and Edward T. Shelbourn; and in favour of the following candidates for the first time : Edward Halliwell, F.I.C., Analyst to the West Riding of Yorkshire Rivers Board, Wakefield ; Arthur John Starey, assistant to Mr.Lawrence Briant, London ; and William Lincolne Sutton, F.I.C., Public Analyst for West Suffolk, East Suffolk, and the boroughs of Norwich, Ipswich, and Bury St. Edmunds. The following were elected members of the Society : Percy T. Adams, Arthur French Angell, John B. Ashworth, Alfred Joseph Bull, Charles Crocker, John S. Ford, C. A. Hackman, Norman Leonard, J. F. Liverseege, Richard Murray, G. E. Scott-Smith, W. P. Skertchly, Harry Metcalfe Smith, Lionel W. Stansell, and W. Northfield Yarrow. The PRESIDENT (Mr. Fisher) said that the Council had been considering the Sale of Food and Drugs Bill recently introduced in the House of Commons by Mr. Walter H. Long (President of the Board of Agriculture), the Solicitor-General, and Mr. T. W. Russell, and had thought it advisable to make some representation to the President of the Board of Agriculture, and to bring before him in a definite way the views of the Society of Public Analysts, I n the forefront of the interview which Mr.Long had accorded to the representatives of the Council was placed the strong feeling which the Council held that there was a necessity for the establishment of what had been termed a Standing Departmental Committee or Court of Reference. The Bill provided that the Board of Agriculture should, after such inquiry as it might deem f26, issue regulations having relation to certain agricultural products. It was represented to Mr. Long, on behalf of the Council, that they would still desire to see a wider and more comprehensive body established, failing which it was suggested that the Local Government Board should have equal powers with the Board of Agri- culture to confer with a strong scientific body in reference to other articles of food and to drugs.Mr. Long did not make any distinct promise on this matter, but it114 THE ANALYST. might fairly be said that he received the Council’s representation sympathetically. In addition to the provision which the Bill contained, that the Board of Agriculture should decide what proportions of extraneous matters were to be permitted in certain articles of food, the Council asked that the subject of preservatives should be definitely mentioned. A suggestion was made with the object of rendering clause 8, which dealt with the admixture of butter-fat with margarine, more clear and definite in meaning ; and also that there should, if possible, be embodied in the Bill definitions of skimmed and separated milk in terms of the percentages of residual fat which they respectively contained.Other suggestions were offered by the Council respecting the effect, of the time limit of twenty-eight days in proceedings against the giver of a warranty ; the reference of samples to the Commissioners of Inland Revenue ; the form of certificates; and the embodiment in the Bill of some definition by which the word food ” might be made to apply to articles which, although not themselves strictly of the nature of food, were used in the preparation or flavouring of food. The following papers were read : “ On a recent Ginger Case,” by E. J. Bevan, Bernard Dyer, D.Sc., and Otto Hehner ; ‘( The Composition of Milk and Milk Products,” ‘‘ An Attempt to compute mathematically the most Probable Limits for Milk,” and a ‘‘ Note on the Estimation of Ether and Alcohol when mixed with Petroleum Ether and other Solvents,” by H. Droop Richmond ; The Estimation of Fat in Milk, using Petroleum Ether as a Solvent,” by H. Droop Richmond and C. H. Rosier ; and ‘‘ Notes on Milk Analysis, including the Molybdate Test for Cane Sugar,” by L. de Koningh. Mr. W. P. Skertchly exhibited a new form of distilling flask for use in water analysis.

ISSN:0003-2654    

DOI:10.1039/AN8992400113

出版商:RSC    

年代:1899

数据来源: RSC

摘要:

114 THE ANALYST. A METHOD FOR THE QUANTITATIVE SEPARATION OF ISOVALERIC AND ACETIC ACIDS. BY ALFRED C. CHAPMAN, F.I.C. (Read at the Meeting on November 2, 1898.) THE quantitative separation of small quantities of isovaleric and acetic acids is not by any means a simple matter. The method of partial neutralization followed by distilla- tion is in this case practically useless, whilst the ingenious method of Duclaux, although aflording an approximate determination of the proportions in which the two acids exist, does not affect their separation. When a solution containing the above two acids free from their homologues has been obtained, they may, of course, be estimated by neutralization with baryta, followed by a determination of the percentage of barium in the mixed salts. This indirect method is open to the objection that any failure to obtain the mixed barium salts in a pure and dry condition (by no means an easy matter) will introduce a very appreciable error into both determinations.Moreover, it is not, strictly speaking, a method for their separation. Having frequently had occasion to estimate the percentages of these two acids when present together in solution, and if possible to obtain them separately for purposes of furtherTHE ANALYST. 115 identification, I was led to make experiments with this object in view. At the outset it seemed likely that a difference of solubility of a metallic acetate and of the corre- sponding valerate in some solvent might offer the best chances of success. Sodium valerate dissolves fairly readily in a solution containing 99.5 parts of acetone and 0-5 part of water, whilst sodium acetate is practically insoluble in that menstruum.The 99.5 per cent. acetone is, in fact, an excellent solvent from which to obtain pure sodium valerate in a crystalline condition. If the commercially pure salt is treated with a sufficient quantity of the solvent at its boiling-point and filtered, beautiful crystals having a pearly lustre separate from the filtrate on cooling, which can readily be filtered by the aid of a pump, and dried in a vacuum over sulphuric acid. The salt purified in this manner was used for the experiments described below. A determination of sodium showed it to be perfectly pure : Found, 18.46 per cent. Na. Calculated, 18.54 per cent. Na. It was in the first place necessary to determine the best conditions for the application of this method, and to ascertain with what degree of accuracy the separa- tion could be effected.Known weights of dry sodium valerate and anhydrous sodium acetate (both powdered) were transferred to a small flask and thoroughly mixed. The requisite quantity of the 99.5 per cent. acetone was then added, and the mixture heated just to its boiling-point for some minutes, a piece of glass tubing passing through a cork in the flask serving to prevent the loss of any appreciable quantity of the acetone. The liquid was then passed through a small asbestos filter into a second small flask, and the residue in the first flask washed with a further quantity of the acetone in two successive portions.The acetone was then distilled off, the residue washed into a platinum dish, evaporated to dryness, treated with sulphuric acid, and weighed as sodium sulphate. The sodium acetate remaining in the first flask and on the funnel waa then dissolved in water, and treated in a similar manner. From the weights of sodium sulphate obtained the amount of acetic and valeric acids can of course be easily calculated. I n the following table some of the results obtained are given : Taken. Found. Skd. Acetate. Sod. Valerate. 0.122 gr. 0.109 gr. 0.124 gr. 0.117 gr. 0.144 gr. 0.093 gr. 0.067 gr. 0.104 gr. 0.250 gr. 0.250 gr. 0.217 gr. 0.238 gr. 0-210 gr. 0.145 gr. -----. 7--- Total. Sod. Acetate. 0.231 gr. 0.122 gr. 0-241 gr. 0.123 gr. 0-237 gr. 0.143 gr. 0.171 gr.0.066 gr. 0.500 gr. , 0.246 gr. 0.455 gr. 0.217 gr. 0.355 gr. ~ 0.211 gr. Sod. Valerate. 0.106 gr. 0.118 gr. 0.090 gr. 0.103 gr. 0.254 gr. 0.235 gr. 0.142 gr. F Total. 0.228 gr. 0.241 gr. 0.233 gr. 0.169 gr. 0.500 gr. 0.452 gr. 0.353 gr. Potassium valerate is also soluble in 99.5 per cent. acetone, and can be obtained from it in pearly plates. Although potassium acetate is almost insoluble in that liquid, the potassium salts cannot be used for the purpose of separation by this method, as the valerate abstracts water from the solvent, and the acetate is converted into a pasty mass. Aqueous Experiments were next made starting with the acids themselves.116 0.102 gr. 0.087 gr. 0.189 gr. 0.157 gr. 0.044 gr. 0.201 gr. 0.153 gr. 0-043 gr. 0,196 gr. THE ANALYST. 0.084 gr.0.187 gr. 0 103 gr. 0.150 gr. 0.041 gr. 0.200 gr. 0.155 gr. 0.040 gr. 0.195 gr.THE ANALYST. 117 method brought before the Society many years ago by Dr. DuprB, the amyl alcohol was fractionated from the spirit, and obtained ultimately along with some ethyl alcohol. It was oxidized, neutralized with barium carbonate, and, in the barium salt thus formed, the barium was determined, from which the valeric acid was calculated. Mr. RICHMOND observed that ordinary fusel oil was a mixture of about equal parts of the active amyl alcohol and the iso-amyl alcohol, and would give a corre- sponding mixture of the two valeric acids on oxidation. It would be interesting to know whether or not the active valeric acid behaved in the same way as the iso- valeric acid.Perhaps the author had made some experiments that would yield information on this point. Mr. HEHNER said he supposed that, as the molecular weight advanced, the sodium salt would become more and more soluble. He inquired whether, in applying the method to other separations, the author would consider it necessary to use 99.5 per cent. acetone, or whether some weaker strength might be used ; and also how a lower acid, such as butyric acid, might be expected to behave under a similar process. Mr. BEVAN asked how the author managed to hit upon 99.5 per cent. acetone, and whether the fractional percentage of water was essential. Mr. CHAPMAN said that want of time had prevented his going beyond the immediate object of the investigation, which was simply the separation of acetic and isovaleric acids, so that he could not at present say anything as to the behaviour of active valeric acid, or of any lower acid. B e intended, however, to continue the investigation, and to ascertain to what extent the process might be employed in determining fusel oil. Mr. Hehner’s suggestion as to the increased solubility of the sodium salt with the rise in inolecular weight was doubtless correct. With regard to the solvent, he thought it probable that, in other separations, other strengths of acetone might be employed. It seemed curious that the presence of such a very small quantity of water should have such a marked effect; but sometimes, he thought, insufficient importance was attached in analytical procedure to the influence on solubilities exerted by a small quantity of some third substance.

ISSN:0003-2654    

DOI:10.1039/AN8992400114

出版商:RSC    

年代:1899

数据来源: RSC

摘要:

THE ANALYST. 117 CAPER TEA. By JOHN WHITE, F.I,C. (Read at the Meeting 012 March 1, 1899.) IN the course of the last two years I have had occasion to examine a considerable number of samples of tea,, particularly of that variety distinguished by the name of caper tea, submitted to me under the Sale of Food and Drugs Act. Prior to this time I had always regarded tea of any description as an article which was sufficiently supervised by the provision made for its analysis and inspection in bond before being distributed for sale. The Local Government Board returns evidence the fact that this arrangement has worked well in the past, for although tea, and especially caper11 8 THE ANALYST. 2.98 6-90 3.84 tea, was found to be largely adulterated in the early days of the Food and Drugs Acts, either by the addition of exhausted or foreign leaves, or by the introduction of a comparatively large proportion of extraneous mineral matter, in the year 1897, of 403 samples of tea analysed by the Public Analysts of England and Wales, only one was certified to be adulterated.Further, it was stated in the Local Government Board Report for 1897, that of 4,289 samples of tea analysed under the Aot during the ten years ending with 1896, only four Fere condemned. In the ANALYST for the present year (vol. xxiv., p. 30) a paper appears by C. Estcourt, in which he emphasizes the fact of the disappearance of adulterated caper tea from the retail market, and quotes a report from the Government laboratory containing the results of analysis of seven samples of caper tea, described as authentic samples out of bond.The following table gives the results obtained by me from samples of caper tea submitted under the Act between June, 1897, and January, 1899. These samples were not confined to any one particular district, but were collected from various parts of the county of Derby. The estimations were made upon the undried tea, and in nearly every instance the figures given represent the mean of three or four separate determinations. The results are expressed in parts per cent. : 2-80 2.80 3.20 10.67 6.00 5.62 6.26 3.10 3-10 Ash soluble in water ... Ash insoluble in water ... Mineral matter insoluble in acid ... ... ... 2. 11.34 2.79 8-55 4.66 2.76 9-44 5.66 The mineral matter which remained 3. 11.31 2.84 8.47 5-10 4.9.90 3.24 6.66 4.40 after boiling with dilute hydrochloric acid, with subsequent thorough washing and ignition, consisted in each instance of clean sharp sand mixed with small stones, among which occurred fragments of quartz, The original mineral matter was not in any sample noticeably magnetic. I do not apprehend any serious difference of opinion as to whether or not these samples are adulterated; it will, I believe, be generally admitted that the extraneous mineral matter shown by these figures is present in too high a proportion to have been '( unavoidably mixed in the process of collection and preparation " of these teas. This is certainly obvious in respect of samples 1 to 6, the results of which will possibly justify the chief purpose of this paper, viz., to show that after having lain dormant for many years, the sophistication of caper tea has again become a practic- able process, and the sale of the spurious product has apparently become possible.Proceedings were successfully instituted against the vendors of samples 1, 2, 3, and 4, and are pending in the case of 6 ; sample 5 will be referred to later. I advised that no action be taken respecting 7 and 8, and also with reference to several other samples containing a total ash of slightly over 8 per cent., as I thought it distinctly undesirable that prosecutions should be undertaken unless the adulteration proved to be of substantial extent.THE ANALYST. 119 I n addition to the eight samples the results of which are set forth in the above table, I have also found nine other samples yielding a total ash ranging from 8 to 8.4 per cent.; the highest percentage of mineral matter insoluble in acid present in these was 2.7, which occurred in one sample, the next highest being 2.56. Some years ago this Society fixed as a limit 8 per cent. as a maximum of total ash to be permitted in genuine tea, when calculated upon the tea dried at 100” C. Were this figure rigidly adopted, these nine samples must perforce be condemned, but this, in my opinion, is a standard that should be interpreted with very considerable discre tion. Some fifty further samples yielded a percentage of total ash varying from 6.2 as a minimum to 7-9 as a maximum, the average being 7.04, and, what I think is especially important, in no instance did the mineral matter insoluble in acid exceed 2.0 per cent.These results indicate what may fairly be held to represent the composition of genuine caper tea, though both A. H. Allen and Wynter Blyth have expressed the opinion that this variety of tea hardly deserves the description of “ genuine,” indeed, the former (‘ believes it to be invariably a factitious article.” Whether this be so or not, caper tea has come to be recognised as a distinct article of commerce, and one that is in great demand, more especially by the lower classes and by those tea-drinkers who prefer tea with what is known as a ‘‘ rough ” flavour. Caper tea is also believed to be of considerable value for use in mixed teas for the purpose of flavouring the mixture ; sample 4 was sold at the high price of 3s.8d. per pound, and was said by the vendor to be of especially superior quality and character. The argument has been raised that it is unfair to purchase caper tea under the Act, inasmuch as it is an article which palpably is adulterated by the tea growers abroad, and that the unfortunate vendor who may be prosecuted here is the innocent victim of circumstances outside his control. I t is also argued that to buy this special variety of tea appears to be an attempt to entrap the unwary trader. These arguments do not appear to me to be either logical or sound ; the Sale of Food and Drugs Acts were passed primarily with the object of protecting the consumer. The process, moreover, by which caper tea is said to be manufactured, viz., by coating the leaves with gum or starch, and subsequently rolling them up into small granules of rounded shape, is in itself highly suspicious.I t seems quite possible that this method was adopted for the purpose of allowing the tea to be loaded with mineral matter, the shape of the finished article being favourable to the concealment of it inside the leaves of the tea. Assuming these conclusions to be correct, it is plain that caper tea should not be allowed to compete unduly with the ordinary kinds of tea. I would suggest that, having regard to the report already referred to from the Government Laboratory, from which it appears that caper tea containing 2-68 per cent. of mineral matter insoluble in acid (I obtain this figure by adding together the sand and the silica less sand) is regarded as genuine, that the presence of 3 per cent. should be considered by Public Analysts to be an adulteration.It is doubtful, however, in view of the result of the appeal Shortt 9. Robinson, whether a con- viction will be obtained until a percentage of 3.5 is exceeded. Sample 5 was certified by me to contain at least 3.5 per cent. of mineral matter consisting of small stones and sand, and became the subject of the above-mentioned120 THE ANALYST. appeal. At the hearing of the case before the magistrates I gave evidence, and a newspaper report of the certificate from the Government Laboratory, given in respect of Mr. Estcourt’s case at Manchester, was produced by the defendant’s solicitox, who, however, neither disputed my analysis nor called any rebutting evidence.Our solicitor objected to the production of this document, on the ground that it was not evidence, but it was read. Eventually the Bench dismissed the mmmons, but granted a case for the decision of the Court of Queen’s Bench. The following is the report of the appeal, taken from the Times of February 9 last : QUEEN’S BENCH DIVISION. (Before Mr. JUSTICE LAWRANCE atid Mr. JUSTICE CHANNELL.) Shortt v. Robinson. This was a case stated by justices of Derbyshire, sitting at Chesterfield, at the hearing of an information against Mark Robinson for selling caper tea adulterated with 3.5 per cent. of mineral matter, consisting of sand, small stones, etc. Mr. J. H. Etherington Smith appeared for the appellant, the inspector ; Mr. Appleton for the respondent, the seller of the tea.The information, taken out under the Sale of Food and Drugs Act, 1875, was heard on October 22. These facts were proved.-William Marples deposed to purchasing the tea at the shop of the respondent on behalf of the appellant, W. A. Shortt, the Inspector of Weights and Measures for the northern division of the county of Derby. The tea was divided into three parts for the purpose of analysis. The result of the analysis was that it contained 3.5 per cent. of foreign ingredients. At the hearing the County Analyst was called, and swore to the above. I n the course of his cross-examination, he was asked whether he had seen in the Grocey news- paper a case heard at the Manchester Police-Court on August 16, in which a Somerset House report showed that extraneous matter was necessarily present in caper tea.The analyst admitted that he had seen the report of the case in a paper, not the Grocer. The appellant’s solicitor objected to this as evidence. The justices allowed the question, though they held that the report was not evidence. The report in the Grocer, however, was attached to the case. The analyst in cross-examination stated that, in the course of sixty-five analyses of caper tea, he had found the amount of sand and stones to be not so much as 2 per cent., and that only six specimens contained as much as 3 per cent. I t was contended for the appellant that an adulteration of 3-5 per cent. having been proved, there must be a conviction. The justices found that the purchaser asked for caper tea, and that such tea was well known as one manu- factured for the purpose of using in small quantities by way of addition to ordinary tea for flavouring it.The justices also found that it was well known that caper, like ordinary tea, was grown under conditions which afforded unusual chances of the introduction of sand and small stones, the tea being grown on friable, sandy soils, and it being a condition of successful growth that rain should be not only very frequent, but copious. They considered that, having regard to these facts, they were not justified in convicting the defendant on so small a percentage as 3.5 of extraneous matter of a nature peculiarly incident to the growth of the articIe. Moreover, it appeared from the evidence of the analyst himself that there was necessarily some per- centage in caper tea of the extraneous matter complained of.They accordingly dismissed the information. The question for the opinion of the Court was whether the justices mere justified in considering, on the facts before them, that a presence of extraneous matter to the extent of 3.5 per cent. did not necessarily constitute an adulteration. Mr. Smith contended that the justices were wrong. They had evidently acted on the report of the Somerse: House authorities set out in the case heard in Manchester. That wasTHE ANALYST. 121 not evidence in the case before them. The analyst might have been asked his opinion of the report. If he had affirmed it, then there might have been something for the justices to act on. He was not asked for that, however.His analysis uncontradicted was sufficient to show adulteration under Section 24. He cited Dargie 2). Dunbar (21 Scottish Law Reports, 536), Regina 2,. Field and others, Justices of Hampshire (64 L. J., M, C., 158). I n the Manchester case the defendant gave evidence that the tea when sold was in the same condition as when i t was brought out of bond. Section 30 provided for there being an analysis of tea in bond. There was no such evidence in this case. The Court dismissed the appeal. Mr. Justice Lawrance said that, in his opinion, the decision of the magistrates ought not to be disturbed. The anaiyst had stated that there was stone, sand, etc., to the amount of 3.5 per cent. in the sample of tea submitted to him. His attention was then called to the report of the Somerset House authorities supplied in another case dealing with caper tea generally. The analyst admitted that he had seen the report.An objection was taken to the admission of the report as evidence of the facts. It was not stated in the case that the analyst expressed any opinion on the report. I n the result, the magistrates apparently brought their own knowledge to bear on the matter, and without calling on the respondent to say whether the tea was in the same state as when it came to him out of bond, dismissed the information, being satisfied that there were always foreign ingredients present in tea. He thought the Court could not interfere in this case. The justices were not wrong in law, unless it were in receiving something as evidence which was not strictly evidence. But the ultimate conclusion at which they had arrived was one to which they were justified in coming.They must have acted on some knowledge of their own. They were entitled to do so, as could be seen by Regina v. Field. He thought, in fact, that they had treated the facts about caper tea as well known, partly, at any rate, because they had read in print in the report from Somerset House that there were usually foreign ingredients present in tea. They thought that the adulterative matter was so near normal in amount as not to justify them in convicting the respondent. The proper course for them to have followed would have been to ask the com- plainant whether he would insist on going on if they intimated that, supposing the facts set out in the report were properly proved, they would not convict.I n all probability the prose- cution in such a case would be given up. The magistrates apparently treated this report as evidence. I n that they were wrong, but i t was only misreception of evidence at the worst, and nowadays, where the misreception of evidence did not affect the result, especially where there had been an acquittal, the Courts would not interfere. The result of this appeal shows once again how far-reaching in its effects a report from the Government Laboratory may be, but the process of reasoning by which the conclusion is arrived at-that because a given sample of authentic caper tea contains 2.68 per cent. of a foreign ingredient, another sample containing 3.5 (or, as I stated in evidence, 3.8 per cent.) is also genuine-does not commend itself to me. 1 am decidedly of opinion that 3 per cent. as a maximum of foreign mineral matter to be present in caper tea is fair and reasonable, and that if it exceeds that figure the tea should be condemned. There does not appear to me to be any good and suficient reason why an amount of foreign material that would not for a moment be tolerated in ordinary black or green tea, should be held to be lawful and proper when occurring in caper tea. Mr. Justice Channel1 concurred. The result of the finding of the justices was right. The appeal must be dismissed.

ISSN:0003-2654    

DOI:10.1039/AN8992400117

出版商:RSC    

年代:1899

数据来源: RSC

摘要:

122 THE ANALYST. ON SOME ANALYSES OF GINGER BY E. G. CLAYTON. (Read at the Meeting, TVedizesday, March 1, 1899.) RECENTLY I had occasion to examine a considerable number of samples of commercial ginger, and the results of the analyses of these samples are stated in the following table, in which there is a rough classification, according to the origin, condition, and quality of the ginger. I t is believed that the series is fairly repre- sentative, the samples having been supplied to, or obtained for, me by well-known spice-dealers. Time did not permit me to carry out a fuller investigation; but the analyses for the most part comprise about a dozen estimations : soluble and insoluble ash; the extracts dissolved by cold water, ether, absolute alcohol (after complete extraction with ether), and petroleum spirit ; essential oil ; alkalinity, calculated as potash, and chlorine, in the soluble ash; and, in solve cases, the ash, alkalinity of the ash, and chlorine, in the cold-water extract.Water and silica were also deter- mined in certain instances, All the series of estimations may be regarded as strictly comparable. The main objects of the inquiry were : (1) To form an opinion whether certain samples submitted to me were, or contained any admixture of, I ‘ spent ” ginger; (2) to ascertain whether any further information could be amassed as to the effects on the composition of ginger of the operation known as washing” ; (3) to study the influence on the analytical figures of the commercial processes of grinding, with removal of the fibre, and scraping or cuttiizg of the surface of the rhizome-this latter operation being alleged to be resorted to with the view of giving the ginger a better appearance ; (4) to collate analytical data from samples of different geographical origins, and in various conditions, as whole, ground, washed, or otherwise ; and ( 5 ) to compare the figures yielded by different market qualities (as indicated by the prices) of the same variety of ginger.I n the table (which includes the results of analyses of thirty-seven samples) five principal series are included : (A) Whole gingers, washed and unwashed; (B) corn- mercially-ground gingers; (C) spent gingers; (D) a series of four samples of the same Cochin ginger at different stages of grinding, etc. ; and (E) samples of similar ginger, washed, scraped, and cut, as well as some of the cuttings and shavings removed from the surface.Included in the table are the results of an analysis of green ginger (F), and of a few estimations made in some samples of whole Cochin ginger (G), previously steeped in the laboratory for forty-eight hours in water and in diluted alcohol. The averages and limits observed are also stated. I desire to express my acknowledgment of the help cheerfully rendered by my assistant, Mr. Henry H. Williams, in the course of these analyses.Table of h'esults. 13.46 6'69 4'35 1'69 1.86 0 9 7 2.94 1 4 5 1'74 -- 13 ? $ ~ , ---_.__--- Ground Cochin Ginger ... 7 , , 7 ,> ... I. OE 32 33 COCHIN GINGER IN I OF PREPARATION FOR SALE. 34 Gingcr The same, ground ; fibre present , x centrifugal machine ; fibre removed Fibre (separated from 33) The same! passed throubh F.G. EFFECT OF HTEEP- WATER AND NG 48 HOURS IN Green Ginger . . . . . . Cochin Ginger (steeped in water) in proof spirit) Cochin Ginger (steeped in water, mixed with one-fourth its bulk of Cochin Ginger (e'teeped Description of Sample. Jamaica Ginger, unwa. Washed Jamaica . . . . . . Cochin Ginger, unwashed Washed Cochin . . . . . ----- , , , , . . . . . . ; , , , . . . . . . ---- Bengal Ginger, unwashed - 1'23 0.04 __I-__ - I 0'31 __ 0.09 , 0.36 1 0.01 - 1 1 ;:ti , ;:;; 0.02 I 0'47 - - - --- 0'04 I 1.41 0.05 A. WHOLE GINGEW, WASHED AND UNWASHED. 3 4 5 6 (Ground in the out removal of the fibre.) Limed Japan Ginger,unw. Washed Japan . . . . . . African Ginger,unwashed Washed African .. . . . ---_- - 0.94 0'14 1 0'45 0'13 - 0.77 10.01 - 1 0'34 I 0.13 - -- ---__-__ ________--- 10.36 1 6'45 1.56 1-87 1.18 3-74 2'98 - 8'17 I 6'85 ~ 1'44 1 1.65 1.14 1 3'32 1 :'ti 1 1'84 - Average figures for Unwashed Gingers Average figures for Washed Gingers ... . . . . . . - - ~ _ _ _ _ _ _ _ _ _ ~ ~~ --l-l-_l-_!-l-L- 11'12 4-81) 1'44 ' 1'47 0.77 4.17 2'74 3'36 1'44 __ 1'89 , 2.33 I - O.d7 1.11 0.54 0.63 1 '03 1.46 1'87 0'28 0-98 0'95 _.- -_ -_ ~- 3'83 2'14 1 2-80 I - - I 0 72 10.13 11'55 1 5'38 1 1.08 I 1.91 15.40 4%' 0'88 1'87 7-56 6'19 0'61 1-57 4-54 j 4'42 0'41 2-12 1 B. 5'48 4.15 2.05 4'29 5.71 6-47 4'14 -- 0'52 0.40 0'18 - 0.4'2 0'32 0'28 -- 2'96 3.84 2-87 3-34 1'43 ~ 1.72 - - 0'33 I - 0'13 i o 03 0.20 0'05 0-33 0'05 0'25 0'23 --- - 1 _- I:, 16+ 17- 18' (&out 90';.per cGt.1 ... (about 50s. per cwt.) ... (about 40s. per cwt.) ... (about 28s. per cwt.) .. Ground Cochin Ginger Ground Cochiii Ginger Ground Cochin Ginger COMMERCIAL GROUND GINGERS. 19 Ground Japan Ginger .., 11'74 20 i Ground African Ginger 12.29' 7'89 1'21 ~ 1-43 10.36 1 6.18 1 0'81 2'11 ~ __ -__ -_ 4.40 4'50 -- 2-02 I 2-41 1 - ' 0'12 I 0'41 0'11 0'09 0 0'007 0'005 0018 0.005 0'005 0.015 0.005 -- - - - 2.40 1 2.96 1 0 2 4 1 0'00 1 0'40 C. SPENT GINGERS. No.21 was Spent Jamaica Ginger, after being ex- h a u s t e d f o r mineral water purposes. No. 22 was a mixture of Spent African and J a m a i c a T i p , after a similar use.) -I )contained much fibre 2-57 3 -04 14'06 11'88 8-06 11.56 10.27 7'62 4.94 4.96 3'76 4-33 2'81 3'46 3-19 3.70 1-89 1'79 3'52 3'55 0.51 0'96 0'82 0.70 0.73 1 *07 0.73 0.78 0%!1 0'76 0'78 1'21 0.78 0'90 0+10 0'24 0'40 0.35 1.31 1'49 0.61 0 '59 1.36 1'90 1'08 1'21 0'67 0'65 1.26 1'18 0.09 0.07 0'12 0'11 0'11 0'07 0'08 0'04 0.15 0'12 0 0 0 0 0 0 0 0 0 'C3 0'03 0.07 0.06 0'08 0.12 0'11 0'12 - - - - 0'52 0'45 0.56 0'92 0.53 0.43 0.49 0.75 1-13 1*08 I 0'84 1'60 0'54 2'05 0'34 2'50 0.02 2.70 0'53 1 2'18 0.03 2.29 0 151 0 1'41 0'34 2'13 0'49 1 2'19 0.31 1 2'06 ~- -- I 7'89 Relieved t o be Jamaica Ginger .. . . . . . . . Cochin Ginger . . . . . . ,, ,, . . . . . . 8 4 ---_____ Averages for Spent Gingers . . . . . . . . . . . 11.62 14.25 11.18 14% 13-09 11 -53 10'39 12.07 11'05 12-94 11.62 - - 12.52 11'12 - - .- - 86'59 - 13-10 13.60 13.30 3'20 0.77 0.76 0.49 1 1-05 1 0'09 I 0" j 0.09 0.007 0-14 0'01 0.13 0'01 0.19 3-03 0.018 0 - - 0.01 0'01 0.01 0'04 - 0.02 - - 0.11 - - - - ___ f Series A.( Highest 15'88 6'45 1'81 1 1.87 1'18 6-19 7'39 3.71 1.20 i 1.24 0.30 35'4 11'73 6'58 1.72 2.00 I 1'15 4'32 6.69 4 2 2 0.88 1-24, 0'46 2.67 15'40 9.37 1.21 1 3.57 1.57 6'47 4.54 4'42 0'41 1-43 I 0.28 2'05 14.06 4'33 1.07 ' 1.49 0'84 2'70 2'57 1'79 0.69 1 0.10 1 0 1.41 11.37, 3.29 ~ 1.M 1-40 1 0 . 4 r 12.05 ~ 4.27 0.87 1.69 0'42 4'64 11.90 4-16 1.08 2'08 0'41 3'61 11.12 5.33 2-26 1 2'b4 0.71 5.72 S * i O 3 W 1'63 1'66 0'78 3 71 9'50 10.45 1.61 1 3-04 3-05 1 5'31 1 1-41 0'36 0.53 0.31 0.72 0'18 0'12 0'06 Unwashed Whole Ginger 1 LoGest Series A. f Higheet Washed Whole Ginger .( Lowest Series €3. t Highest LINITS IN SERIES A, u, AND c. 3-48 I 3-84 0'33 1.43 1'72 0'13 1.13 1.90 0'15 0'43 1 0.61 1 0'04 Commercial Ground Gingcr 1 LoGest Series C.Highest .Spent or Exhausted Ginger{ Lowest . - - . n [ 31 I Whole-washed Cochin 3'37 4-59 - - - 0'48 3-19 3'85 - - 0.38 1'86 3'01 0-35 - - 3'52 0 '40 4'55 - - 2-74 ' 2'36 I - I 0.03 0'20 3-18 ' 3.92 0.71 1 0'10 0.72 E. EKKECT OY f 35 Washed Cochin Ginger, SCRAPIXIO. AND { I I scraped and trimmed CUTTING. 36 Cuttings from the same 2.10 ~ 0.27 3'10 0'21 ' 0'34 I 1-38 --7 I I I-1-1- 3'45 1.36 - I - 0.03 1 0'37 I * (0) set down here, as probably correct for spent ginger, neglecting the figures for Nos. 29 and 30, which I believe to have contained some unexhausted ginger.124 THE ANALYST, The figures obtained, of course, in the main confirm those of other observers, but two or three points may be touched upon.In the estimations of moisture, it was noticed that after prolonged drying in the water-oven many of the samples began to gain in weight, this being due, I suppose, to oxidation. Hence it was rather difficult to arrive at constant weights, but the lowest of a series of weighings was taken in each instance. The effect of washing in diminishing the percentages of some of the constituents, such as the ash, soluble ash, cold aqueous extract, etc., is clearly Bhown; and a similar influence appears to be exerted to a certain extent by grinding, removal of the fibre, and the operation of cutting or scraping the exterior of the rhizome. But the figures have also shown that what I at one time thought possible is not the case; namely, that by the combined effect of all these commercial processes- washing, scraping, cutting, grinding, and separation of fibre-the composition of genuine ground ginger might be so altered or reduced as to approximate to that of spent ginger.Some of the results obtained clearly indicate, at all events as regards Cochin ginger, that even after all these operations have been carried out, the per- centage proportions of many, if not most, of the constituents remain sensibly- indeed, considerably-above the corresponding numbers found in spent ginger. I do not know what might prove to be the case with Japan ginger ; the figures do not go far enough to show. The above conclusion is opposed to my earlier anticipations and belief ; but some of the later results, notably the figures obtained with the samples constituting series E in the table, have been entirely convincing.The determinations of the ethereal extract and alcoholic extract (after removal of everything soluble in ether) were effected in a Soxhlet apparatus, the first occupying from two to three days, the second from three to four days. The alcoholic extracts appear to be less than those obtained by other observers; but the last alcohol extraction-fluid was in a number of cases tested, and found to leave prac- tically no residue. Moreover, as it seemed possible that in some instances the extraction with ether had not been carried far enough (in spite of the long time it occupied), and that some matter had been left behind, to be removed by the absolute alcohol, an experiment was made to test this point.Duplicate estimations of the two components were made in one of the samples, absolute alcohol being used first, the extract dried to constancy, weighed, and then treated with ether. The resulting ethereal extract was dried until constant, and weighed. The numbers obtained were : ... Alcoholic extract ... ... ... 0.65 per cent. Ethereal ,, ... ... ... ... 3.73 ,, By the other process (using ether first and alcohol last) the same sample (No. 30) had yielded : Alcoholic extract (after ether extraction) ... 0.75 per cent. Ethereal extract ... ... ... ... ... 3-55 ,, The fair agreement of the two pairs of estimations would seem to point to the substantial accuracy of the rest of these determinations, and to indicate that theTHE ANALYST.125 matter remaining for extraction by absolute alcohol, after ethereal treatment, may be somewhat lower than is supposed,provided that there has first been complete extraction with ether. I t will be seen that the fixed extract removed by petroleum spirit was found to be a tolerably constant figure in the genuine samples, and an attempt was made to determine approximately in each case the essential oil of ginger, by a process somewhat akin to that originally described by Dr. Thresh, namely, extract- ing the ginger with ether, air-drying and weighing the extract, and then drying in the water-oven to constancy; but it was thought possible that the method might be advantageously modified by the substitution for ether of petroleum spirit (by which less of the resinous and other constituents of ginger are extracted than by most other solvents).The figures resulting from this modified process are decidedly lower than those previously obtained, and obviously very variable. Of course, the method is necessarily j mperfect . Chlorine was found to be practically absent from the soluble ashes of the samples of spent ginger ; the two exceptions at the end of the series of spent ginger samples I believe to have been, not exhausted ginger only, but to have contained some admixture of unexhausted ginger. Curiously enough, very small quantities of chlorine appeared in most of the ashes of the cold aqueous extracts of the spent ginger samples. Possibly this might be explained by the presence of some soluble organic compound containing chlorine.The samples Nos. 15*, 16*, 17* and IS*, were different market qualities of the same kind of ginger, namely, Cochin ginger ; it is remarkable that the proportions of the principal constituents diminish as the price increases ; and the question arises whether the real quality of a sample may not sometimes be sacrificed to mere appearance-whiteness, and so forth. DISCUSSION. The PRESIDENT (Mr. Fisher) said it seemed to him that washing ginger till all its valuable constituents disappeared was but little different from mixing it with exhausted ginger, seeing that the result was the same in both cases. It appeared possible, however, that excessive washing was allowed to take place through ignorance on the part of those engaged in the trade.Mr. ALLEN desired to ask what figures the author would take as minimum limits in genuine ginger for soluble ash and for cold water extract, the latter deter- mined directly on the ginger, and not after treatment with alcohol and ether. If ginger was exhausted as completely as possible with water, it would still yield an appreciable proportion of soluble ash. He would like to hear if the author had any information as to the limits of silica in exhausted ginger. This constituent was occasionally present in very considerable proportion. He was much interested in the specimens of exhausted ginger free from chlorides. Mr. Stock and other analysts, and he (Mr. Allen) himself to a limited extent, had determined, not the alkalinity, but the actual potash in the soluble ash of ginger and other plant-products, a factor which sometimes yielded valuable information.His practice, he might mention,126 THE ANALYST. was to estimate soluble ash both by difference and by direct determination by evaporation, which latter method generally gave the higher result, Dr. DYER said that he had recently analysed, in connection with a case in which both he and the author had been interested, a series of samples which he believed were duplicates of many of those referred to in the paper. His conclusions were in agreement with those of the author. The question had been raised at the time by a member of the ginger trade, whether the paring of ginger might not affect the results of its analysis, and particularly the percentage of soluble ash.He (Dr. Dyer) had at the moment not felt prepared to say that it might not, for little was known as to the distribution of the salts contained by the root. The samples which he and the author had both analysed consisted of Cochin ginger of various kinds and in various stages of manufacture - pared and unpared, parings, and fibre separated during grinding. The results of the analyses indicated that any legitimate process to which the ginger might be submitted produced practically no variation in its composition, that is to say, no such variation as could give rise to a suspicion of admixture with spent ginger. One of the samples approximated in composition to what might be regarded as partially exhausted ginger, but that sample had been submitted to a process of excessive washing.There was no evidence that properly-conducted washing resulted in any approach to what might be called exhaustion. I t was, however, an undoubted fact that some ginger-washers-for ginger-washing was a trade-steeped the ginger in hydrochloric acid for the purpose of removing lime from its surface ; and it was obviously necessary to afterwards steep the ginger in water to get rid of the acid. It seemed to him that no sample so treated could properly be regarded as unexhausted, seeing that such washing largely deprived it of both strength and flavour, and so partially exhausted it. He thought that the discussion at present going on in the trade on this subject would have the effect of altogether stopping the washing of many kinds of ginger that were now quite unnecessarily washed. Mr. CLAYTON said it seemed rather difficult on the spur of the moment to lay down limits which would carry authority. He thought he might suggest that 1 per cent. would about represent the lowest limit of soluble ash in genuine ginger, but he only made the suggestion tentatively and with diffidence. I n a sample which he had been assured was genuine, but which was of unknown origin, he had found 1.43 per cent. of soluble ash. That was the lowest figure for soluble ash that he had actually met with in genuine ginger, apart from one sample of washed Japan ginger. He quite agreed with Mr. Allen as to the difficulty of getting out all the soluble ash by exhaustion. This not only applied to treatment with water, but also with alcohol and ether. He was unable to express any opinion as to silica, not having included this point in his investigations; nor had he determined the actual potash present, as he was aware had been done by Mr. Stock. He might mention that the prices of four of the samples referred to in the paper-viz., Nos. 15, 16, 17, IS-were respectively ~ O S . , ~ O S . , ~ O S . , and 28s. per cwt., and it was curious to note that, as the price roBe, the total ash, soluble ash, cold-water extract, and most of the other constitbents diminished.

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DOI:10.1039/AN8992400122

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年代:1899

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T€IE ANALYST. 127 I ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS. I I , Total FOODS AND DRUGS ANALYSIS. The Examination and Characteristics of Commercial Fennel Seed. A. Jucke- nack and R. Sendtner. (Zeit. Untersuch. Nahr. Genussm., 1899, ii., 69-75.)-The authors have examined a large number of the principal kinds of fennel seed found in the German market, viz., German, Itdian, Macedonian, and Galician, with the object of obtaining data for the detection of exhausted and coloured seeds. The moisture, mineral matter, aqueous extract, alcoholic extract, and the earthy impurities and mineral constituents corresponding with these, were determined on specimens of each variety with the following mean percentage results : ____-____ Saxon fennel ... do. extracted Mineral Matter. Aqueous Extract.Alcoholic Extract. Substance. 1 Substance. Substance. Substance. Substance. I Substance. -I-- /--*---, ---- Water. Natural I Dry Natural I Dry Natural Dry 12.09 7445 I 8,480 21.10 ' 24-00 10.24 13-22 7.74 ~ 5.444 I 5.900 6.40 I 6.93 4.23 4.58 -___ I-- I ---- __ ~._____ The following table shows the effect of steam extraction on the composition of the seed : ~ In order to detect the presence of exhausted seeds, from 3 to 5 C.C. of the fennel are shaken in a reagent-cylinder with from 3 to 4 volumes of 96 per cent, alcohol, and allowed to stand for a short time. The extracted seeds become dark or black, while the genuine seeds retain their original colour. The supernatant alcohol varies from dark green to pale green according to the proportion of extracted seeds in the mixture.A second test consists in mixing from 2 to 3 grammes of the seed with 20 C.C. of water in a small basin, and allowing the mixture to stand, when the genuine seeds float (on account of their higher percentage of fat, which repels the water) and retain their colour, while the extracted seeds become dark and fall to the bottom. A difference can also be observed under the miscroscope, the oil-streaks in the genuine fennel being more or less refractive to light, instead of, as in extracted seeds, being dull and black. The ribs of extracted seeds are browner in colour and less sharp in outline than untreated seeds. The authors conclude from their analyses that the following limits may be taken as the lowest for genuine fennel seed :138 THE ANALYST.1 German. i Per cent. Moisture ... ... ... ... I 11.5 Mineral matter calculated on the ' dry substance (excluding earth) I 8.0 Aqueous extract (on dry substance) 1 23.5 Alcoholic extract (on dry substance) ~ 12.0 - - --I__--- ~- _ _ _ Italian. Macedonian. Galician. Per cent. 1 Per cent. Per cent. --------- 10.0 1 9.5 I 10.0 8.0 8.0 8.0 24.0 , 24.0 I 24.0 13.5 135 14.5 - _. - - - The Assay of Liquid Extract of Ipecacuanha. H. Wilson. (ktmer. Jozm. Pharm., 1899, lxxi., 73-77.)-The author criticises the method of determining the alkaloid in this preparation, as given in the British Pharmacopceia of 1898 (p. 115), asserting that it is complex and tedious, and that a considerable proportion of the alkaloids is lost in the lead precipitate. In its place he recommends the following method : 20 C.C.of the strong liquid extract are diluted with an equal volume of water, and the alcohol removed by evaporating the mixture on a water-bath to less than half its volume. After the addition of 1 C.C. of sulphuric acid, the liquid is trans- ferred to a separating funnel (the dish being washed out with 20 C.C. of water) and extracted three times with 10 C.C. of a mixture of equal volumes of chloroform andTHE ANALYST. 129 Ipecacuanh a Extract. 1. 2. Mean -___. _- - -_ - - - I Officinal Process. Alkaloids Alkaloids lost in extracted. Lead Precipitate. Gramme. Gramme. Gramme. Gramme. - Total Alkaloids. ~ A ~ o $ o ~ ~ ' ~ d . i 0.386 0-031 0.417 i 0.417 0.393 0-028 0.421 j 0.426 0.389 0-029 0.419 0.421 The author considers that at present the alkaloids of ipecacuanha cannot be accurately determined by titration. For, if it be assumed that the alkaloids consist of emetine with molecular weight 248 and cephaeline (molecular weight 238), in about equal proportions, each C.C. of decinormal acid should correspond with 0.0241 grarnme of the mixed alkaloids. But in practice the results obtained by a volumetric estima- tion using this factor are from 50 to 60 milligrammes lower than the results of the gravimetric methods. This, in the author's opinion, is probably due to the presence of the third alkaloid, which Paul and Cownley believe to have a higher molecular weight that either of the others. C. A. M.

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DOI:10.1039/AN8992400127

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年代:1899

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THE ANALYST. 129 TOXICOLOGICAL ANALYSIS. The Isolation and Identiflcstion of Sulphonal in Forensic Work. C. Kippen- berger. (Zeit. Untersuch. Nahr. Gewussm., 1899, ii., 75-91.)-I. Isolation of Sulphoizal. -The usual method of extracting sulphonal from cadaveric remains consists in extract- ing the substance with hot alcohol, evaporating the extract, dissolving the residue in hot water, filtering, evaporating and purifying the residue by crystallization from boiling alcohol. According to the author, the preparation thus obtained may be so contami- nated with organic impurities as to render the identification of sulphonal uncertain. From his investigations it appears that 100 c.c, of benzene (B.P. 80"-82" C.) dissolve 8.01 grammes of sulphonal, 100 C.C. of petroleum spirit (B.P.30"-50" C.) 0.06 gramme, and 100 C.C. of chloroform 32.5 grammes. Its solubility in other solvents is : Water, 500 parts; boiling water, 15 parts; ether, 133 parts ; alcohol, 65 parts; boiling alcohol, 2 parts. Toluene and acetone dissolve it in considerable quantities, and carbon tetrachloride dissolves it sparingly, The following method of quantitative isolation is recommended when sulphonal has been detected qualitatively. The dry or only slightly moist material is extracted with chloroform or benzene on the water-bath, and the extract filtered and evapor- ated. The residue is treated several times with small quantities (2 to 4 c.c.) of petroleum spirit, which removes fat and colouring matter, and leaves the sulphonal as a white mass. If cholesterin was present in the original substance, it is separated from the sulphonal by treatment with water, and extracting the sulphonal from the130 THE ANALYST.aqueous solution with chloroform or benzene. This treatment can also be used to separate sulphonal from the xanthin bodies, which are only sparingly soluble in water. The method of isolation and purification also effects a separation from these bases, owing to their insolubility or sparing solubility in benzene, and their fairly ready solubility in petroleum spirit. When putrefactive decomposition compounds are simultaneously present, the author's method of extracting alkaloids with glyceriu tannic acid solution (ANALYST, xx., 201) often gives satisfactory results. If vegetable alkaloids have been also isolated, they can be readily separated by precipitating them from an acid solution by means of iodine in potassium iodide.It should not be lost sight of that fatty oils dissolve a considerable proportion of sulphonal on heating, which they only deposit very slowly on cooling, although in the cold they only take up Blight traces. In the method described by Hilger and Tamba (Arch. d. Pharm., 1887, 225, 408) for the separation of ptomaines and alkaloids by means of oxalic acid solution, the sulphonal remains permanently dissolved. 11. The Xdenti$cation of XzdphonaZ. -Sulphonal, or diethyl-sulpho-dimethyl- methane (CH,),C( S02CzH5)2, forms odourless crystals, which are neutral in reaction, and to most people tasteless. I t is unacted upon by cold concentrated sulphuric acid, by boiling concentrated nitric acid, by bromine, or by boiling solutions of alkaline hydroxides. It melts at 125" to 126" C., and volatilizes at 300" C with slight decom- position.Several tests for its identification have been based on the formatiou of strong odours attributed to mercaptan, on treating it with different substances. Thus, Vulpius heats it with twice its weight of potassium cyanide ; Ritsert uses pyrogallol ; Scharz, charcoal ; and Strobel, zinc chloride. When sulphonal is heated with twenty times the amount of dry sodium acetate, mercaptan and hydrogen sulphide can be detected in the decomposition products. The author has attempted to estimate the mercaptan in this reaction by absorbing it with a solution of silver nitrate, and collecting the silver mercaptide, but with only partial success.When sulphonal is heated with magnesium powder, a sublimate is obtained which consists of malodorous sulphides of various composition, with traces of oily thioalcohols which solidify to a crystalline mass on cooling. On heating a mixture of manganese peroxide and sulphonal, white acid vapours with a penetrating smell are obtained, and the sublimate is a perfectly white substance with no trace of the yellow oil formed in the magnesium powder reaction. A similar reaction is obtained with lead peroxide, barium peroxide, platinum black, and alkaline nitrates, with the formation of oxidation products of the thioacetones derived from the decomposition of the aulphonal (thioacetone oxides). When a mixture of sulphonal and an alkaline hydroxide is heated in a, silver basin until the mass assumes a reddish tint, and then cooled, the residue on extrac- tion with water and filtration furnishes a solution which becomes dark on treatment with ferric chloride, reddish-violet with sodium nitro-prusside, and on acidification deposits sulphur. C. A. M.

ISSN:0003-2654    

DOI:10.1039/AN8992400129

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年代:1899

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THE ANALYST. 131 ORGANIC ANALYSIS. Estimation of Hydrogen and Methane by Fractional Combustion with Copper Oxide. E. Jager. ( J . GasbeZeucht. 1898, xli. 764; through Chem. Zeit. Rep. 1898 335.)-The processes for separating methane from hydrogen by fractional combustion with air sufler from the disad-vantage that owing to the limited size of the burette, only small volumes of the gas can be taken for analysis. The author finds that if a mixture of hydrogen, methane and nitrogen is passed two or three times over copper oxide heated to 250" C. as indicated by the thermometer the bulb of which is in contact with the tube the hydrogen alone is oxidized; and by raising the temperature to a red heat aEter removing the thermometer the methane can afterwards be burnt, Small corrections are necessary for the alterations in volume of the oxide during reduction and for the amount of atmospheric oxygen in the combustion tube; but these can easily be ascertained The apparatus required is partly illustrated in the ac-companying sketch.The Determination of Arsenic in Glycerin. F. H. L. A. C. Langmuir. (Journ. Anzer. Chem. SOC. xxi. 133-136.)-1n this modification of the Polenske method 15 to 20 grammes of crude soap glycerin or 15 to 20 grammes of saponification- or C. P. glycerin are diluted to 100 C.C. with hot water and carefully boiled down with 200 C.C. of concentrated nitric acid and 12 C.C. of concentrated sulphuric acid until sulphuric acid fumes are copiously evolved the nitric acid being finally expelled by strongly heating.The cooled liquid is diluted to 50 C.C. and run slowly into a Marsh apparatus drop by drop the flow being regulated so that not more than two bubbles of gas per second pass the lead nitrate wash-bottle. Any escape of undecomposed hydrogen arsenide can be detected by placing a strip of paper soaked in mercuric chloride in the further end of the heated tube. The mirror section of the tube is finally separated from the rest and weighed before and after the removal of the mirror. The arsenic content in saponification-glycerins averaged 0.00018 to 0.00030 per cent. whilst crude soap-lye glycerins gave 0.00064 to 0.01 per cent, The Gutzeit method gives fairly good indications for comparison with known quantities when mercuric chloride is einployed as the detecting agent the limit of delicacy being about 0.00010 per cent.but the silver nitrate used by Gutzeit gives very imperfect results. c. s. ____ - ___ The Flash-Point of Dilute Alcohol and other Organic Bodies. P. N. Raikow. (Chem. Zeit. 1899 xxiii. 145.)-The author suggests that a determination of the flash-point of inflammable organic substances in the ordinary Abel apparatus may frequently be of service in judging their degree of concentration or of purity 132 THE ANALYST. For instance absolute ethylic alcohol flashes at 12" C. ; addition of 0.5 per cent. of ether reduces it to 9" ; presence of 2 per cent. of ether lowers the flash-point to 2.5" C. ; so that even 0.1 per cent. may be recognised and estimated. The introduc-tion of 1 per cent. of benzene to monochlorobenzene causes the flash-point to fall from 27.5" to 24"; so that 0.1 per cent.may also be estimated in this case. The operation is carried out exactly as in testing petroleum but the water-bath and annular air-jacket of the Abel apparatus should be filled with hot warm or ice-cold water air snow etc. according to the height of the flash-point expected. Further experiments are in progress; in the meantime the author submits a curve and table of the flash-points of diluted ethylic alcohol. These show that the rise is not in proportion to the amount of water that there is no break in the curve at the point where maximum contraction occurs (51.9 v/v spirit) as should happen if 8 definite hydrate were formed and that alcohol flashes until it contains 97 v/v of water.FLASH-POINTS OF AQUEOUS ALCOHOL. Barometer 710-713 mm. I j 1 Alcohol v/v. 100 . 98 . 96 . 94 . 92 . 90 . 85 . 80 . 75 . 70 . 65 . 60 . 55 . 51.9 . 50 . 45 . 40 . Alcohol v;~ 30 Flash-point. 13.25 14 16.5 J 17.75 19 19.75 21 21.25 22.25 23 15.75 1 24.75 26-25 i I I . . . . . . . . . . . . 8 7 6 5 4 Difference per 5 v/v. 2.5 2 1.25 1.25 0.75 1.25 0-25 1 0.75 1 0.75 1-5 . . . . . . . . . . . . . . . . Flash-point, 27-75 29.5 33-25 36.75 41.75 43 44.25 45.75 47 49 50.25 52.6 55 58.25 62 68 Difference per 5 v/v. . 1-75 . 3.75 . 3.5 . 5 . 7.25 . . .13 F. H. L. The Separation of Unsaturated Fatty Acids from one another K. Farn-steiner. (Zeit. Unters. Nahr. Genussn?,. 1899 ii. 1-27.)-(a) Experiments on the Separation of Oleic Acid as Lead Elaidate.-Various methods of converting oleic acid into elaidic acid were tried and it was found that the largest yield could be obtained by saturating the fatty acid with nitric oxide and converting this into nitrogen peroxide by introducing oxygen. The most favourable conditions were with the temperature at 10" to 20" C. and with 20 to 25 C.C. of nitric oxide to each gramme of oleic acid. A special apparatus is described in which the reaction was carried out in a flask from which the larger proportion of the air was first removed. The acid obtained was hard dry and crystalline melted at about 43" C.and contained from 82 to 86 per cent. of pure elaidic acid. The lead salt of the impure elaidic acid behaved like those of the saturated fatt THE ANALYST. 133 acids as regards its solubility in ether and benzene 100 C.C. of the former dissolving 0-0086 gramme and 100 C.C. of the latter 0.0040 gramme at 16" to 20" C. The author made use of this fact to determine the amount of acid not converted into elaidic acid in his experiments with pure oleic acid the lead salts being treated with benzene in the method described in his paper on the separation of saturated from unsaturated fatty acids (ANALYST xxiii. 285). Although so far he has been unable to obtain sufficiently constant results with the elaidic reaction for a quantita-tive method to be based upon it he considers that applied in the method described, it is a valuable qualitative test for the presence of oleic acid and for determining the purity of that acid.(b) Experiments 01% the Estimation of Oleic Acid as CL Barium Salt.-Dry barium oleate is insoluble or dissolves only in traces in hot benzene. On adding absolute alcohol to the benzene and boiling the salt is only dissolved with great dificulty ; but with weaker strengths of alcohol it is readily dissolved and is deposited as a crystalline powder on cooling. The separation of barium oleate from benzene (con-taining alcohol) is so complete that it appears suitable for the quantitative separation of oleic acid from other unsaturated fatty acids whose barium salts are soluble in benzene etc.The following experiment with olive oil illustrates the general method employed : About 1-3 gramme of olive oil was saponified and the hot soap solution precipitated with barium chloride. The precipitate was washed with water and dissolved in 50 C.C. of benzene containing 2.5 C.C. of 95 per cent. alcohol. The next day the precipitate was filtered off and dissolved in 50 C.C. of benzene containing 10 C.C. of the alcohol the precipitate from this being recrystallized from 50 C.C. of benzene containing 20 C.C. of alcohol. The filtrates yielded soluble barium salts containing 0.190 gramme of fatty acids corresponding to 14.9 per cent. of the oil. The fatty acids recovered from the insoluble barium salts were converted into lead salts and separated into saturated fatty acids (9.95 per cent.) and oleic acid (70.9 per cent.) by the author's process (ANALYST xxiii.285). The oleic acid yielded a firm elaidic acid melting at 41" to 42" C. Earthnut oil contained 30.3 per cent. of fatty acids forming soluble barium salts. h lard with an iodine value of 49-0 gave the following results Solid acids 42.2 ; oleic acid 39.2 ; and fatty acids forming soluble barium salts 13-9 per cent. Cocoa-butter was found to contain Solid acids 59.7; oleic acid 31.2; and other acids, 6.3 per cent. In the case of butter-fat cotton-seed oil and sesame oil the author was unable to separate the oleic acid in an approximately pure condition by this method a con-siderable proportion of the barium oleate remaining dissolved in the benzene while a corresponding amount of tshe barium salts and other acids were found in the barium oleate precipitate.By treating the liquid fatty acids of butter-fat with nitrogen peroxide as in a, about 45 per cent. of elaidic acid was obtained from which result the amount of oleic acid in the fat was calculated to be about 20 per cent. T b barium salts of the fatty acids can be prepared directly from the fats by saponifying them with a solution of bariutn hydroxide in equal volumes of benzene and methyl alcohol, The saturated fatty acids melted at 57" C 134 THE ANALYST. (c) The Detection aid Quantitative 'Estimation of Linolic Acid,-A method of determining linolic acid is based on the insolubility of linolic tetrabromide in cold petroleum spirit the precipitate being collected and weighed as described by the author in his former paper (ANALYST xxiii.286). The results thus obtained under varying conditions of bromination (temperature - 10" to + 20" C.) with different oils and fats are summarized below. Cottowseed oil total fatty acids yielded a tetrabromide melting at 113" to 114" C. (uncorr.) the amount corresponding with (1) 18.9 ; (2) 18.45 and 18.2 per cent. of linolic acid The quantity obtained from the liquid fatty acids in two determinations corresponded with 23.0 and 23.9 per cent. or 17.2 per cent. and 18.2 per cent respec-tively on the total fatty acids. Sesame oil (with 12.1 per cent. of solid acids) was found to contain in its total acids (1) 16.4 and (2) 15.2 per cent. of linolic acid. A second sample extracted in the laboratory gave the following results Solid acids 14.1 ; liquid acids 86.7 ; and linolic acid 12.6 per cent'.Earthnut Oil,-As the total fatty acids yielded no insoluble bromide the more unsaturated fatty acids were concentrated by treatment of the barium salts with benzene as in b and the acids recovered from the soluble barium salts brominated in petroleum spirit. The insoluble bromide melted at 113-5 and had a molecular weight of 602.5. The unsaturated acids brominated amounted to about 30 per cent. of the weight of the oil and the linolic acid obtained to about 6 per cent. Olive Oil.-This was examined in the same way as the earthnut oil and the acids from the soluble barium salts treated with petroleum spirit. The bromination products did not dissolve completely in the hot solvent a powdery residue remaining (probably linolenic hexahromide).The solution deposited crystals melting at 113" C. on cooling. Rape-seed Oil.-On brominating the total fatty acids a considerable quantity of an insoluble substance of which only traces were soluble in petroleum spirit but which was much more soluble in ether was obtained. From its melting-point on crystalli-zation from benzene (178" C.) the author regarded this as linolenic hexabromide. Almond Oil.-The amount of tetrabromide (M.P. 113-114" C.) obtained from the total fatty acids corresponded with 5.97 per cent. of linolic acid. Mustard-seed oil gave bromides melting at 178" to 179" C. and 111" to 112" C. respectively. The yields corresponded with 4 per cent. of linolenic acid and 4.5 per cent.of linolic acid. Butter-Fat.-This was prepared in the laboratory from the milk of cows whose fodder for a long time previously had contained cotton-seed meal. The liquid fatty acids yielded an appreciable quantity of au insoluble bromide which had all the characteristics of linolenic hexabromide. The bromide of linolic acid was not found. Lard.-Five grammes of the fat were separated by the barium method (b) and the acids from the soluble barium salts brominated in petroleum spirit. The bromination product dissolved completely in the hot solvent but on cooling deposited a small quantity of two bromides one of which was identified as linolic tetrabromide, while the more insoluble which melted without purification at 165" waa probably linolenic hexabroinide THE ANALYST.135 Horse-Fat.-The liquid fatty acids yielded an insoluble bromide corresponding with 9.9 per cent. of linolic acid in the fat. Ox-Tallow.-This like lard was found to contain a small amount of linolic acid and traces of linolenic acid. As regards the detection of linolic acid by the formation of its oxidation product (sativic acid) the author points out that Hazura in all his researches prior to 1888, gave the melting-point of sativic acid as 160" to 162" C. but that in a paper published in that year in conjunction with Griissner the melting-point was given as 173" C. On the other hand Fahrion found the melting-point of his sativic acid to be 152" C. The author is inclined to believe that Hazura's acid melting at 160" to 162" C. was not pure sativic acid but contained an isomeric substance.C. A. M. The Constants of Various Train-Oils. W. Fahrion. (Chem. xeit. 1899 xxiii., 161.)-The constants of various kinds of fish-oils are collected in the following table. To determine the saponification and Hehner numbers 2 or 3 grarnmes of the sample were heated on the water-bath with 10 or 15 C.C. of 2N alcoholic alkali the spirit removed the soap dissolved in hot water placed in a separating funnel acidified with dilute hydrochloric acid and when cold extracted with 30 or 40 C.C. of petroleum ether (b. p. 75") allowing the mixture to rest over-night. The aqueous liquor was drawn off from below the small proportion of oxidized fatty acids in solution being neglected and the petroleum ether poured off from above; the insoluble acids washed in warm ether and the whole of the solvent evaporated on the water-bath, weighing the residue to obtain the fatty acids plus the unsaponifiable matter.This was dissolved in 40 or 50 C.C. of alcohol and titrated with aqueous potash to yield the ( ( inner saponification number." The neutral liquid was extracted with petroleum spirit the extracts washed with 60 per cent. alcohol and dried to give the unsaponifiable matter. By calculation the molecular weight of the fatty acids was thus arrived at. The insoluble oxy-acids in the separating funnel were taken up in warm alcohol evaporated weighed and the ash determined ; the difference being the oxidized acids themselves. The sum of the fatty acids oxy-acids and unsaponifiable matter gave the Hehner number.The iodine value was estimated with the Waller solution working for twenty-four hours in the dark and arranging as accurately as possible for an excess of 50 per cent. of the iodine absorbed-uniformity is particu-larly necessary in this operation. I t should be noted that when the catch of dorse (Baltic cod) is small brown liver oils appear on the markets which contain 5 per cent. or more of unsaponifiable matter. This does not always point to adulteration but simply to a sort of fermentation and the use of a high temperature during extraction of the oils. Such products of course are of less value and 3 per cent. should be taken as the limit. With the exception of herring-oil (No. 9) all were completely liquid and translucent at ordinary atmospheric temperatures which shows that the greater part of the palmitin had already been precipitated by cold.The colours quoted were those given by a layer 2 em. thick 136 Pale dorse Brown liver 1896 , 1897 Sardine oil .,. . Stickleback oil . . Herring oil . . , Japan fish oil . 1 7 . . ,7 9 . 11 l . . . 91 91 9 . t * THE ANALYST. CONSTANTS OF FISH-OILS. yellow . brown . . , . , yellow , orange . yellow . . , yellow-brown pale yellow . brown -yellow pale yellow . reddish-yellow yellow . ked .*. . Description. ~ Colour. 180.0 96.52 Iodine lumber. Seal oil . . . . . . Whale oil . . . Y Y . > . . 166.2 162'4 140.6 159.8 191.7 167.9 160.9 162.0 123'5 164.0 157'6 135.7 108.5 100.1 138% 155.9 160% 149.0 146.2 116-2 106.1 iotw reddish-yellow reddish-yellow pale yellow .reddish-yellow Acid num-ber, 1.8 23 -5 30 *9 139.9 19-2 21 *7 4.6 21-6 44.6 10.8 34.2 12.3 34.5 28-2 9.2 34.6 46'4 1.4 43.1 49.5 4-2 51.4 '& Inner Saponifi- Hehner cation I number. iumber."l 174.2 174.2 185.2 177.2 179-5 181.5 178.5 185 9 189.1 181.4 180.0 183.8 175.1 177.0 181.0 195.9 184.4 184-9 177.3 176.7 95'46 97.05 95.60 96-65 97'08 95.78 95.64 95-52 96-58 97'04 96.82 96.51 9726 95.79 95.84 96-83 95.98 96.70 95.19 96-49 - ~~~ Un-saponi6. able matter P.C. 0.78 1.30 1 5 0 1-91 0.48 1.01 G.63 1.73 0.99 0.52 0.67 0.82 0 9 6 0.79 1.68 1.00 1.68 0.29 0.79 0.69 0.70 1.77 OFY-acids p.c. 0.23 0.61 1 -29 1 *49 0.61 1 *35 0-94 0.62 1 a59 1 *16 0.75 0.41 0 '62 0 -49 0.18 3.11 0.63 0'29 0.75 0 -57 1 '44 0.39 Fatty weight acids P.L 95-48 94'61 92.67 93.65 94.51 94.19 95.51 93.43 93.06 93.84 95-16 95-81 95'34 95'23 95'40 91-68 93.53 96.25 94.42 95-44 94.33 94.33 of fatty acids. 294.1 294'1 298'2 301 -0 285.7 297 *7 299.5 287.4 291 *9 282.8 281.7 295 -7 296% 290.2 305.1 290.0 289.4 285.3 286.7 289.0 293'9 298.9 T F. H. L. Valuation of Resin. A. Heupel. (Zed. aizgew. Chem. 1899 17l.)-The results of more than 1,000 determinations of the acid and saponification numbers of colophony gave an average of 100 for the acid number and 170 for the saponification number and a similar difference was found between these numbers with other resins.The author agrees with Schick that the determination of constants as a basis for the valuation of colophony is useless. Out of many thousands of casks of resin which he has examined he has never found two to give the same constants. H. H. B. S. Contributions to our Knowledge of Colophony. R. Schick. (Zed. angew. Chem. 1899 172.)-The author replies to Dieterich's remarks in the Zeit. angew. Chem. No. 5 . He again points out that Dieterich's "acid number," obtained by allowing the resin to stand for two hours in the cold with excess of alcoholic potash and titrating back can be neither an acid number nor a saponification number since it is greater than the number obtained by direct titration and less than that obtained on standing for twelve hours in the cold.He considers that the sharpness of the end-reaction and the regularity of the decomposition which takes place on direct titration point to the correctness of this method of determining the acid number. Among other reasons for objecting to the direct method of titration Dieterich states that this method gives numbers below the calculated acid number of abieti THE ANALYST. 137 anhydride. The author replies to this by referring to the numbers given by Dieterich himself (155.85 to 170.80 and 168.00 to 183*50) and by pointing out that Perrenoud has already shown (Chem.Zeit. 1885) that colophony does not consist solely of abietic anhydride. Further Dieterich himself asserts in the same paper that the resins (and therefore presumably colophony) are to be regarded as mixtures of very uncertain composition. The author does not attach any importance to the iodine number as a means of valuation the fluctuations (as stated by Dieterich) being too great (cf. ANALYST, this vol. 77). H. H. B. 5. - - _ _ _ _ _ A Reaction of Gallic Acid Tannin and Pyrogallol. G. Griggi. (Boil. Chim fawn. 1899 xxxviii. 5 ; through Chem. Zeit. Bep. 1899 29.)-When a few C.C. of a 1 per cent. solution of gallic acid are shaken with 1 C.C. of a 3.3 per cent. solution of potassium cyanide a bright ruby-red colour is produced which disappears on standing but is re-formed every time the tube is agitated in presence of air.A drop or two oE hydrogen peroxide also colours the bleached liquid similarly. A 1 per cent. solution of tannin or pyrogallol gives a yellowish-red colour with potassium cyanide. and the subsequent decolorization is slower. Agitation and hydrogen peroxide reproduce the tint but an excess of the latter gives a permanent yellowish-brown colour with gallic acid and a characteristic dirty-white precipitate with tannin. 3'. H. L. A New Method of Estimating Tannin. L. Vignon. (&dl. Soc. C'hiwz. 1898, xix. 923-926.)-This is based on the fact that ungummed silk can absorb tannin quantitatively from an aqueous solution leaving the other substances which usually accompany it (gallic acid glucose etc.). The silk is used in large excess of the tannin, which should be in dilute solution the proportion being about 5 grammes of silk to 0.1 gramme of tannin in 100 C.C. of water. The tannin is absorbed after four or five hours at 50" C. and can then be determined by any of the usual methods; titration of the liquid with permanganate using indigo as indicator gave the most exact results. The silk (ungummed) is prepared by being washed and rinsed in distilled water and dried and 5 grammes are used for each estimation. Absorption by silk has the advantage over absorption by violin strings or hide-powder of being much more rapid while unlike hide-powder it does not yield soluble organic matter to the solution. Finally the colour of the silk after the absorption enables one to estimate comparatively the degree of coloration of the tannin-an indication which it3 of value to the dyer and to the tanner. C. A. M

ISSN:0003-2654    

DOI:10.1039/AN8992400131

出版商:RSC    

年代:1899

数据来源: RSC

摘要:

THE ANALYST. 137 INORGANIC ANALYSIS. Gravimetric Estimation of Sulphuric Acid in presence of Iron. The Importance of the Ionic Theory in Analytical Chemistry. F. W. Kuster and A. Thiel. (Zeits. nnorg. Chem., 1899, xix., 97.)-It is now well known that sulphuric acid cannot safely be thrown down by means of barium chloride from a solution con-THE ANALYST. taining dissolved iron; for inasmuch as the impurity in the precipitate takes the form of ferric sulphate, which is decomposed into oxide on ignition, part of the acid is lost, and attempts to purify the barium sulphate by extraction of the iron simply lead to increased deficiency in the yield, because they remove that portion of ferric oxide which, left behind, would partially take the place of the weight of sulphuric anhydride that was not originally combined with barium.The usual method of precipitating the iron first with ammonia and treating the fifiltrate with barium chloride consumes much time, and is also inaccurate, since some of the acid is carried down with the ferric hydrate as st basic sulphate. The authors find, however, that when barium chloride is added to a liquid in the presence of iron, the precipitate falls with absolute purity provided the iron is either (1) in an insoluble form, i.e., a state of suspension ; or (2) is in solution combined with a complex ion, e.g., tartaric, or preferably oxalic acid. A solution of sulphuric acid and ferric chloride containing 2 atoms of iron to 3 of sulphur (the proportion occurring in pyrites) was prepared of such a strength that 25 C.C.should theoretically yield 0.713 gramme of BaSO,. This volume was diluted with an equal amount of cold water, and an excess of ammonia (20 c.c.) in- troduced. The whole was heated almost to the boiling-point with constant stirring, and, neglecting the ferric hydrate, 15 C.C. of about 10 per cent. barium chloride solution were dropped in slowly. Eight C.C. of 10 per cent. hydrochloric acid were next added, and the liquid kept warm and well mixed for two hours. It was then set aside to cool for half an hour, the liquid run off through a filter, and the residue treated several times in succession with 2 C.C. of cold HCl and 30 C.C. of boiling water, allowing each extraction to take place for thirty minutes. Finally the barium sulphate was washed three times by decantation with boiling water, brought on to the filter, washed, dried, and weighed.The precipitate was per- fectly white, and weighed from 0.7109 to 0.7142 (mean 0.7125) gramme : 0.5 d l i - gramme, or 0.07 per cent., less than that required by theory. I n the second process, 25 C.C. of the acid ferric chloride liquor were mixed with 15 C.C. of water and 25 C.C. of a cold saturated solution of ammonium oxalate, heated to the boil, precipitated with 15 C.C. of barium chloride, and acidified with 15 C.C. of HC1. The further treat- ment was precisely as above : the yield was almost pure white, and weighed 0.7115 or 0.7129 (mean 0.7122) gramme, i,e., 0.8 milligramme, or 0.11 per cent., less than demanded by theory. A tartaric acid solution gave- very similar results, and the barium sulphate was ultimately of perfect purity ; but the employment of this acid is not to be recommended, for much more iron is first carried down, and the individual yields show wider variations among themselves.I n describing their methods and experiments, the authors express some surprise that the idea of converting the iron into some soluble compound other than sulphate before precipitation does not appear to have occurred to the numerous investigators who have endeavoured to overcome the difficulty of obtaining a barium sulphate uncontaminated with this troublesome and exceedingly common impurity. As Jannasch has conclusively shown that the precipitated iron always takes the shape of ferric sulphate, it is clear that such precipitation cannot occur unless the liquid contains ions both of ferric iron and of sulphuric acid.The latter obviously cannotTHE ANALYST. 139 be avoided; the former may, either by throwing the metal entirely out of solution, or by combining it with some more complex ion which does not behave in an analogous fashion. The effect of precipitating and removing the iron as hydroxide is not per- fectly satisfactory, and even with the greatest care must lead to a loss of some 0.5 per cent, of the sulphuric acid. F. H. L. - - Estimation of Boric Acid. F. A. Gooch and L. C. Jones. (Zeits. anorg. Chem., 1898, xix., 417.)-The process described by Thaddkeff (ANALYST, 1898, xxiii., 165) suffers from two defects : there is no proof that a mixture of potassium hydrogen fluoride and potassium borofluoride can be quantitatively separated by extraction with potassium acetate solution ; while, as the present authors have definitely ascertained, when such a mixture is evaporated in presence of hydrofluoric acid, some of the boric acid volatilizes. Thadddeff’s method always gives too high a result, presumably because the former source of error is the more serious; obviously it can only be exact if they happen to neutralize one another.The modified form of Rosenbladt’s process, in which a borate is distilled with methylic alcohol and acid into a solution of a known weight of lime, is reasonably accurate. The acid may be nitric or acetic, and should only be employed in suficient excess to decolorize phenolphthalein, a few drops more being added occasionally during the distillation. I n this way the necessity for having such a large quantity of lime, as recommended by Moissan, is avoided.Particularly when nitric acid is adopted, the dried residue of lime and boric acid requires very cautious heating before the actual ignition; even with acetic acid it should be handled carefully to prevent loss, It is perfectly possible to ignite the original calcium oxide to constant weight, and to weigh it without appreciable error in spite of its hygroscopic nature; but to avoid the troublesome manipulation, the authors suggest sodium tungstate as an absorbent. This salt is fused with a small excess of tungstic acid (to remove traces of carbonate); a known weight of lime (4 to 7 grammes for 0.2 to 0.3 gramme of boric oxide) is dissolved in water, placed in the receiver of the distilling apparatus, surrounded with ice-cold water, well agitated with the boric acid vapours, allowed to rest half an hour, and then evaporated, melted, and weighed. Using acetic acid, the residue must be ignited till it is perfectly colourless on cooling. Either nitric, acetic, or sulphuric acid can be employed-excess of the latter is objectionable. Various examples are quoted; the results are fair, but tend to be a little too low, F. H. L.

ISSN:0003-2654    

DOI:10.1039/AN8992400137

出版商:RSC    

年代:1899

数据来源: RSC

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THE ANALYST. 139 APPARATUS. Estimation of Carbon and Hydrogen in Volatile Organic Liquids. F. W. Streatfield and L. Eynon. (Chemical News, vol. lxxix. [2045], p. 50.)-The apparatus devised by the authors for this purpose consists of a strong, moderately large test-tube containing a small quantity of mercury and fitted with a triple-bore caoutchouc stopper. The tube from the supply of air140 THE ANALYST. or oxygen dips into the mercury, to prevent backward diffusion; a second tube leads to the combustion tube; and a glass rod with a flattened head passes loosely through a tube fixed in the central bore of the stopper, communication with the external air being prevented by a, joint of rubber tubing. The substance is introduced into the test-tube, enclosed in a sealed bulb which is broken by means of the rod, and the vapour is carefully expelled into the combustion tube by a current of air or oxygen entering through the supply tube.If the vapours are capable of attacking the caoutchouc fittings, the apparatus can be inverted, the air-supply tube being in such event bent upon itself so at3 to dip into the mercury seal. c. s. . - - - . _ _ _ I _ ~ A Condenser for Extraction Work. C. G. Hopkins. (Joz~nz. Anzw. C h m . SOC., vol. xx. [12], pp. 965, 966.)-This condenser obviates the trouble caused by - condensed atmospheric moisture collecting on the outer surface of Liebig or Allihn condensers and running down over the extraction apparatus. It; consists of a closed tube a, of thin glass, 25 em. long and 25 mm. external diameter, into the top of which are sealed two glass tubes about 6 mm.in diameter, as water inlet and outlet, one of thein extending nearly to the bottom of a. The whole is enclosed, by sealing, in a stronger glass tube h, 30 mm. in internal diameter, drawn out below, for a length of 8 mm., to 10 mm., and ground off obliquely at the end. A lateral tube c. 5 cin. long and 12 mm. wide inside, is sealed on to h, about 3 em. from the top, to facilitate connection with a drying tube. The vapour being distributed in a thin layer over a large cooling surface, greater efficiency is obtained ; the risk of breakage, through unequal expansion below and above the water-line, is nil; and the outer surface of the condenser is too warm to condense atmospheric moisture. c. s. & 6 MISCELLANEOUS. Antiseptics in Food.-A paper on the subject of preservatives or antiseptics in food was read by Dr. Alfred Hill, the Medical Officer of Health and Public Analyst for the City of Birmingham, at a recent meeting of the Incorporated Society of Medical Officers of Health. A discussion ensued, in which a number of medical officers of health and public analysts took part, and ultimately the following resolutions were adopted : (1) That the Incorporated Society of Medical Officers of Health strongly disapproves of the practice of adding preservative cheinicals to milk and other foods. (2) That if preservative chemicals are added to any food, a full disclosure as to the nature and amount thereof should be inade to the purchaser.

ISSN:0003-2654    

DOI:10.1039/AN8992400139

出版商:RSC    

年代:1899

数据来源: RSC

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NOTE ON BORIC ACID I N MILK SAMPLES. BY E. G. CLAYTON. (Read at the Meeting, March 1, 1899.) BORIC ACID was tested for qualitatively in 403 samples of milk received by me for analysis during the years 1893-98, and the following .is a record of the results : Total number of samples, 403; of these 164, or 40.6 per cent., contained boric acid. Thus : In 1893, of 45 samples, 28 contained boric acid, or 62.2 per cent. ? 7 1894, 7 ) 28 7 ? l7 ? 7 7 , ? I 60.7 7 , 7 , 1895, ,, 92 ? I 43 ?, ? 9 ?, 46.7 ? ? ,, 1896, ,, 62 ,, 29 7 7 7 , ,? 46.7 9 , ), 1897, ,, 108 ,, 37 ? ) 7 , 9 , 34-52 ?, 9 , 1898, 9 , 68 f ? 10 9 , 7 7 ,, 14.7 ? I - 403 164142 THE ANALYST. In the table on the opposite page the samples are classified according to quality, and the relative amounts of boric acid added.The numbers of adulterated, doubtful (that is, poor or inferior, or probably adulterated), and genuine samples are also shown. Watered milks and samples with the fat abstracted are indicated respec- tively by the letters w and s ; both sophistications together are shown by W/S. The figures demonstrate a gradual diminution in the use of boric acid, possibly owing to the introduction of formaldehyde, which, however, was not tested for in any of these samples. DISCUSSION. The PRESIDENT desired to ask by what method the author had tested for boric mid. He himself had latterly found that the most expeditious way was one which had been described several years previously in the ANALYST (xvi., ISO), viz., to heat 0.5 C.C. of the milk in a dish with a little weak and slightly acid tincture of turmeric. The reaction was thus obtained more readily than by any other method that he had tried. Mr. CLAYTON said that he had tested the ash after acidification by hydrochloric acid with turmeric paper, confirming the test by applying alkali to the turmeric paper after drying. The alkali used was generally potash, but sometimes ammonia.

ISSN:0003-2654    

DOI:10.1039/AN899240141b

出版商:RSC    

年代:1899

数据来源: RSC